NDB allow not allowing access with valid ip

I have a nbd server setup with the following config

[generic]
    user = nbd
    group = nbd
    port = 98745
[export]
    exportname = /dev/ubuntu-vg/lv0
    authfile = /etc/nbd-server/allow

without an allow file this works flawlessly.

after adding the following allow file

10.0.0.0/24

with an ip of 10.0.0.10 i get

Negotiation: ..Error: Connection not allowed by server policy. Server said: Access denied by server configuration

and on the server

Spawned a child process
virtstyle ipliteral
connect from 10.0.0.10, assigned file is /dev/ubuntu-vg/nfs-lv
client address does not match 2/10: address family mismatch (IPv4 vs IPv6?)
message repeated 2 times: [ client address does not match 2/10: address family mismatch (IPv4 vs IPv6?)]
Client '10.0.0.10' is not authorized to access
Negotiation failed: Connection reset by peer

any thoughts? I'm stumped, as per the docs here this should work as is. to be thorough I've also added 127.0.0.1 and 10.0.0.10 to the allow file and received the same results, trying each line individually as well.

I get ip checking isn't exactly secure but if it makes things lightly more difficult for malicious actors I'd like to enable it. Please also make sure suggestions use the new style format.

This just happened to me, a few newbie mistakes I figured out after trial and error:

1. The configuration documentation says String, but don't put it in quotes, that doesn't work.
2. Authfile = (Nothing to right of =) will open it up for all access.
3. "Connection not allowed by server policy" - this can ACTUALLY mean it does not have read permissions to file, or the file name/path of the export is incorrect.
4. Debugging the server is easier if you start it on command line with -d nbd-server -d -C /etc/nbd.conf so you can see any errors.

I noticed that your exported file "/dev/ubuntu-vg/lv0" doesn't match your assigned file in log "/dev/ubuntu-vg/nfs-lv"

Here is my working nbd.conf, no auth file is required as I defined it as empty. I am on version 3.21

[generic]
  allowlist = true
  listenaddr = your.ip.add.ress
[archiso]
  exportname = /z/systemrescue-9.00-i686.iso
  authfile =
  readonly = true
  port = 10809

Good luck to you!